Performance of cold air insertion at the cutting interface in the griding process of AISI 4340 steel with an aluminum oxide grinding wheel

Abstract

Grinding is a machining process characterized by the use of an abrasive rotary tool,to perform the removal of small amounts of material, providing a fine tolerance and a good surface finish, thus being used as an finishing industrial process. However, the heat generated at the grinding process is a very intense due to the high cutting speed employed. This heat can cause thermal damage at the piece, compromising its quality. For these reasons, it is necessary to use cutting fluids in the grinding process. However, most of the time, these fluids have a quimical composition that can damage the environment and human health and also present high added value to their use. In order to avoid damages caused by cutting fluids, grinding is currently carried out under the minimum amount of lubricant (MQL). However, although this technique has a great lubrication capacity, the removal of heat is not as efficient as compared to the use of the fluid in the grinding. In order to solve the refrigeration problem presented in the MQL technique, it is proposed by this work the use of compressed air at a low temperature together with the application of the MQL technique. Therefore, in order to verify the efficiency of this technique and verify its applicability, the following output variables will be analyzed: arithmetic average roughness (Ra), circularity deviation, diametral grinding wheel wear, G ratio (relation between volume removed from material by volume of grinding wheel), cutting power, acoustic emission, vibration, optical microscopy of the test piece and micro-hardness vickers. Thus, it aims to understand the phenomena involved in the process and contribute to the scientific and industrial environment, making the technique applicable, which can add value to the product and contribute to an environmentally cleaner manufacturing.